Wow, this DIY was a huge headache.
No way this will take anyone 15 mins.
It took me over an hour.

Here are some awesome tips for anyone doing this job:

1) When you're trying to unclip the plug, get it so the clips are unseated and can stay that way b/c you've loosened it slightly.
From there, use a flathead screwdriver to pry it away. This was the only way I got the plug off. WHEW! Otherwise, it's impossible to remove the plug.

2) It was a nightmare trying to pull the FSU out. There is no room for 2 hands, yet you need 3 if you want light!
I was trying to pull it out by grabbing the damn socket thing. I tried to grab that little hole with needlenose pliers. I must have done this for 20 mins.
THEN I finally reached around to the BACK, and PUSHED it out. Holy ****, that made it 100x easier.

3) When trying to install the new FSU, you need to push the harness/wires UP AND OUT of the way.
Yet, there is NO extra room anywhere. (And by now, your neck and arms are starting to tire)
So, use a screwdriver to hold the wires UP over the cavity in order to get the FSU past them.

Lastly, I was never able to fully seat my new FSU. It just would not go all the way in.
There is no way to get it past that release latch again.
I spent 15 mins trying to push it in, and then said F it.
There is no way it can fall out with the jack plugged in.
Did this happen to anyone else?

My FSU wasn't even defective, but for $50 I figured I'd just change it.
But the original FSU in my 2001 530i seemed to have the updated heat sink design. (Same number of prongs)
It did not have the fewer and thicker prongs. So, this DIY was probably totally unnecessary.